SANTIAGO  - Chile is suing mines operated by BHP, Antofagasta and Albemarle over alleged environmental damage caused by their operations in the northern Salar de Atacama salt flats, a court said late on Thursday.

The State Defense Council (CDE) launched its legal action in the environmental court over the pace of extraction from the Monturaqui-Negrillar-Tilopozo aquifer - an important source of ground water - it said had impacted the fragile ecosystem.

Chile is the world's top copper producer and a major source of lithium used in electric vehicle batteries.

Increased exploitation "caused serious, permanent and irreparable deterioration of the aquifer, of the Tilopozo plains, of the fauna, and of the life systems and customs of the Peine Indigenous Community," the First Environmental Court said, citing the lawsuit.

"The extraction of various amounts of water by the sued mining companies would have caused damage that was foreseeable, since they were aware of the maximum limit of descent that the aquifer could have," it added.

Antofagasta's Zaldivar copper mine said in a statement on Friday that it had extracted water in accordance with what was allowed in its permits, adding that there was "no evidence of environmental damage."

Escondida, the world's largest copper deposit controlled by BHP, said "it is fully convinced that it has acted in accordance with its obligations" and that it had technical studies showing there was no deterioration in the Tilopozo area of the aquifer.

Albemarle, one of the main lithium miners in Chile, did not immediately respond to a request for comment.

Chile's leftist President Gabriel Boric has made environmental protection a key focus of his administration, including rights over water, since taking office in March.

In March, Chile's environmental watchdog SMA fined Escondida for exceeding the maximum level allowed for water extraction since 2005. Also last month, the SMA filed charges against Albemarle for irregularities in its operation at the salar.

The CDE, a state body answerable to Boric, is demanding that the environmental damage be made good and that the mining firms take steps to ensure such events are not repeated.

The use of water in the Atacama has become an important regulatory issue for lithium miners, who use brine to extract the light metal that is a critical component in the manufacture of batteries. Chile is the world's no. 2 producer of the battery metal.